Problems to be solved by visual basic..Pls.Help me

hello!!im just new in this field,im still studying as computer programmer in a Tesda school here in our town..

here's the problem,,i hope you can help me solve this tonight..

A car travelled 10 minutes in gravel,15 minutes in sand, 20 minutes in asphalt, 25 minutes in mud..How can i run this,,that when i type for example 27 minutes so the car will be on the asphalt,,when i type the number of minute the corresponding place will appear in the textbox..